Hello, I hope no one minds, I just updated the http://www.coreboot.org/Development_Guidelines page and added a little comment on how to use "patch" to test patches against your clean local repository. Here is what it says:
Testing your Patch
Patches can be tested against your clean local repository by using the patch command. Just copy your new patch file to the top-level directory of your clean local repository and issue this command:
patch -p0 < filename.patch
Thanks - Joe